.box {
  width: 200px;
  height: 200px;
  background-color: yellow;
}
.box {
  margin: 10px;
}
.box .text1 {
  color: green;
}
.box .text2 {
  color: blueviolet;
}
.box .text3 {
  color: pink;
}
.box :hover {
  background-color: red;
}
.box_header {
  background-color: aqua;
}
.box_footer {
  background-color: blue;
}
.box_content {
  background-color: brown;
}
:root {
  --mainColor: green;
}
.box2 {
  background-color: var(--mainColor);
  width: 200px;
  height: 200px;
}
